scholarly journals Identification and Characterization of Novel Genetic Markers Associated with Biological Control Activities in Bacillus subtilis

2006 ◽  
Vol 96 (2) ◽  
pp. 145-154 ◽  
Author(s):  
Raghavendra Joshi ◽  
Brian B. McSpadden Gardener
Keyword(s):  
Biological Control ◽  
Bacillus Subtilis ◽  
Genetic Markers ◽  
Plant Pathogens ◽  
Plant Growth Promoting Rhizobacteria ◽  
Subtractive Hybridization ◽  
Pythium Ultimum ◽  
Suppressive Subtractive Hybridization ◽  
Antibiotic Biosynthesis ◽  
Wide Range

Suppressive subtractive hybridization (SSH) was used to identify genetic markers associated with biological control of plant pathogens by Bacillus subtilis. The genomes of two commercialized strains, GB03 and QST713, were compared with that of strain 168, which has no defined biocontrol capacities, to obtain a pool of DNA fragments unique to the two biocontrol strains. The sequences of 149 subtracted fragments were determined and compared with those present in GenBank, but only 80 were found to correspond to known Bacillus genes. Of these, 65 were similar to genes with a wide range of metabolic functions, including the biosynthesis of cell wall components, sporulation, and antibiotic biosynthesis. Sixteen subtracted fragments shared a high degree of similarity to sequences found in multiple B. subtilis strains with proven biocontrol capacities. Oligonucleotide primers specific to nine of these genes were developed. The targeted genes included five genes involved in antibiotic synthesis (bmyB, fenD, ituC,srfAA, and srfAB) and four additional genes (yndJ, yngG, bioA, and a hypothetical open reading frame) not previously associated with biological control. All nine markers were amplified from the commercialized B. subtilis strains GB03, QST713, and MBI600, with the exception of ituC, which was not detected in GB03. The markers also were amplified from four other B. subtilis isolates, but they were not amplified from other related Bacillus strains, including the plant growth-promoting rhizobacteria IN937a and IN937b. Sequencing of the amplified markers revealed that all seven of the isolates that scored positive for multiple markers were genotypically distinct strains. Interestingly, strains scored positive for the amplifiable markers generally were more effective at inhibiting the growth of Rhizoctonia solani and Pythium ultimum than other Bacillus isolates that lacked the markers. The potential utility of the defined genetic markers to further define the diversity, ecology, and biocontrol activities of B. subtilis are discussed.

scholarly journals Microbial antagonists against plant pathogens in Iran: A review

2020 ◽  
Vol 5 (1) ◽  
pp. 404-440 ◽  
Author(s):  
Mehrdad Alizadeh ◽  
Yalda Vasebi ◽  
Naser Safaie
Keyword(s):  
Biological Control ◽  
Chemical Control ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Plant Diseases ◽  
Agricultural Products ◽  
Control Measures ◽  
Wide Range ◽  
Plant Disease Management ◽  
Published Research

AbstractThe purpose of this article was to give a comprehensive review of the published research works on biological control of different fungal, bacterial, and nematode plant diseases in Iran from 1992 to 2018. Plant pathogens cause economical loss in many agricultural products in Iran. In an attempt to prevent these serious losses, chemical control measures have usually been applied to reduce diseases in farms, gardens, and greenhouses. In recent decades, using the biological control against plant diseases has been considered as a beneficial and alternative method to chemical control due to its potential in integrated plant disease management as well as the increasing yield in an eco-friendly manner. Based on the reported studies, various species of Trichoderma, Pseudomonas, and Bacillus were the most common biocontrol agents with the ability to control the wide range of plant pathogens in Iran from lab to the greenhouse and field conditions.

scholarly journals Trichoderma: a beneficial antifungal agent and insights into its mechanism of biocontrol potential

2020 ◽  
Vol 30 (1) ◽  
Author(s):  
Ria Mukhopadhyay ◽  
Deepak Kumar
Keyword(s):  
Biological Control ◽  
G Protein ◽  
Plant Pathogens ◽  
Hydrolytic Enzymes ◽  
Main Body ◽  
Antifungal Metabolites ◽  
Camp Pathway ◽  
Wide Range ◽  
Biocontrol Potential ◽  
Chemical Pesticides

Abstract Background Agriculture is an indispensable part of any country to feed the millions of people but it is under constant threat of pests. To protect the crops from this huge yield loss recently, chemical pesticides are used. Though chemical pesticides have shown effective results in killing the crop pests, it causes negative impact on the environment as well as humans. So to find an eco-friendly alternative, biological control methods are being used. Main body Biological control is a great renaissance of interest and research in microbiological balance to control soil-borne plant pathogens and leads to the development of a better farming system. In biological control, genus Trichoderma serves as one of the best bioagents, which is found to be effective against a wide range of soil and foliar pathogens. Genus Trichoderma is a soil inhabiting green filamentous fungus, which belongs to the division Ascomycota. The efficacy of Trichoderma depends on many abiotic parameters such as soil pH, water retention, temperature and presence of heavy metals. The biocontrol potential of Trichoderma spp. is due to their complex interaction with plant pathogens either by parasitizing them, secreting antibiotics or by competing for space and nutrients. During mycoparasitic interactions, production of hydrolytic enzymes such as glucanase, chitinase and protease and also signalling pathways are initiated by Trichoderma spp. and the important ones are Heterotrimeric G protein, MAP kinase and cAMP pathway. G protein and MAPK are mainly involved in secretion of antifungal metabolites and the formation of infection structures. cAMP pathway helps in the condition and coiling of Trichoderma mycelium on pathogenic fungi and inhibits their proliferation. Short conclusion Trichoderma being an efficient biocontrol agent, their characteristics and mechanisms should be well understood to apply them in field conditions to restrict the proliferation of phytopathogens.

scholarly journals Bacillus subtilis from Potato Rhizosphere as Biological Control Agent and Chili Growth Promoter

2019 ◽  
Vol 23 (2) ◽  
pp. 179
Author(s):  
Nur Prihatiningsih ◽  
Heru Adi Djatmiko ◽  
Erminawati Erminawati ◽  
Puji Lestari
Keyword(s):  
Bacillus Subtilis ◽  
Plant Growth ◽  
Plant Pathogens ◽  
Biological Control Agent ◽  
Plant Growth Promoting Rhizobacteria ◽  
Dry Mass ◽  
Growth Promoter ◽  
Soluble Phosphate ◽  
Root Mass ◽  
Colletotrichum Spp

Bacillus subtilis is an antagonist bacteria  that inhibits the growth of fungal and bacterial plant pathogens. The B. subtilis has roles as biocontrol agents and plant growth promoting rhizobacteria (PGPR). This research aimed to evaluate the potency of B. subtilis isolates (B209, B211, and B298) as a biocontrol agent to anthracnose (caused by Colletotrichum spp.) and as PGPR to increase the growth of chili plants. The experiments were divided into two batches. The first batch was conducted in the laboratory to evaluate the characteristics of B. subtilis (as biocontrol) and PGPR (phosphate solubility, producing IAA and nitrogen). The second batch was conducted in the field in Rempoah Village, Baturraden Regency, Banyumas District, with 5 treatments and 6 replications. Parameters observed were inhibition percentage to Colletotrichum spp., disease intensity, the component of PGPR, plant growth of chili, and phatosystem. The results showed that B209, B211, and B298 isolates inhibited the growth of Colletotrichum spp, with the highest inhibition percentage on B298. B209, B211, and B298 have characteristics as PGPR, i.e. the ability to soluble phosphate, to produce IAA and nitrogen. The ability of B298 to promote plant growth was shown by the increase of plant height, leaf number, plant dry mass, and dry root mass (38.0%, 54.7%, 61.7%, 61.8%, respectively). B298 and B211 could increase the fresh crop mass (41.2% and 37.1%) and fresh root mass (36.4% and 34.4%). B298 and B209 were similar in increasing the root length (25.2%). Root volume could be increased by 33.3% by applying B211 isolate. B209 was the best isolate to reduce anthracnose up to 80.36%.

scholarly journals Volatile antimicrobials from Muscodor crispans, a novel endophytic fungus

Microbiology ◽  
2010 ◽  
Vol 156 (1) ◽  
pp. 270-277 ◽  
Author(s):  
Angela M. Mitchell ◽  
Gary A. Strobel ◽  
Emily Moore ◽  
Richard Robison ◽  
Joe Sears
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Endophytic Fungus ◽  
Amazon Basin ◽  
Plant Pathogens ◽  
Phytophthora Cinnamomi ◽  
Pythium Ultimum ◽  
Propanoic Acid ◽  
Human Pathogens ◽  
Black Sigatoka ◽  
Wide Range

Muscodor crispans is a recently described novel endophytic fungus of Ananas ananassoides (wild pineapple) growing in the Bolivian Amazon Basin. The fungus produces a mixture of volatile organic compounds (VOCs); some of the major components of this mixture, as determined by GC/MS, are propanoic acid, 2-methyl-, methyl ester; propanoic acid, 2-methyl-; 1-butanol, 3-methyl-;1-butanol, 3-methyl-, acetate; propanoic acid, 2-methyl-, 2-methylbutyl ester; and ethanol. The fungus does not, however, produce naphthalene or azulene derivatives as has been observed with many other members of the genus Muscodor. The mixture of VOCs produced by M. crispans cultures possesses antibiotic properties, as does an artificial mixture of a majority of the components. The VOCs of the fungus are effective against a wide range of plant pathogens, including the fungi Pythium ultimum, Phytophthora cinnamomi, Sclerotinia sclerotiorum and Mycosphaerella fijiensis (the black sigatoka pathogen of bananas), and the serious bacterial pathogen of citrus, Xanthomonas axonopodis pv. citri. In addition, the VOCs of M. crispans killed several human pathogens, including Yersinia pestis, Mycobacterium tuberculosis and Staphylococcus aureus. Artificial mixtures of the fungal VOCs were both inhibitory and lethal to a number of human and plant pathogens, including three drug-resistant strains of Mycobacterium tuberculosis. The gaseous products of Muscodor crispans potentially could prove to be beneficial in the fields of medicine, agriculture, and industry.

scholarly journals Bio-efficacy of Bacillus subtilis against Damping off Disease in Brinjal

2019 ◽  
pp. 1-11
Author(s):  
Deepak Awasthi ◽  
Mukesh Srivastava ◽  
Shubha Trivedi ◽  
Abhishek Mishra ◽  
Supriya Dixit ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Protein Content ◽  
Plant Pathogens ◽  
Growth Parameters ◽  
Germination Percentage ◽  
Total Protein Content ◽  
Liquid Formulation ◽  
Damping Off ◽  
Vigor Index ◽  
Wide Range

Bacillus sp is one of the biocontrol agents are extensively used in management of fungal diseases of crop plants, exhibiting mycoparasitism against a wide range of plant pathogens. In the present investigation Efficacy of Bacillus subtilis was tested against Pythium aphanidermatum under glass house and field conditions. With regard to the germination and seedling growth parameters, the treatment T2 (liquid formulation of Bacillus subtilis @10 ml/L)  recorded the highest germination percentage (92.59%), shoot length (59.3 cm), root length (24.3 cm), vigor index (7740.52) and yield (22.67 mt/ha). This was followed by the treatments T3, T1 and T4 in the decreasing order of merit. In the biometric observations also, 10 ml/L and 20 ml/L concentration of liquid formulation of Bacillus subtilis recorded statistically significant results. Observations on total protein content in brinjal plants treated with different concentrations of Bacillus subtilis revealed that treatment T2 was found best in both field and glass house conditions yielded highest protein as 0.44mg/ml and 0.30mg/ml respectively. The least values of germination, growth parameters, protein content and yield were observed in untreated control.

scholarly journals Fatty Acid Competition as a Mechanism by Which Enterobacter cloacae Suppresses Pythium ultimum Sporangium Germination and Damping-Off

2000 ◽  
Vol 66 (12) ◽  
pp. 5340-5347 ◽  
Author(s):  
Karin van Dijk ◽  
Eric B. Nelson
Keyword(s):  
Fatty Acids ◽  
Biological Control ◽  
Fatty Acid ◽  
Linoleic Acid ◽  
Plant Pathogens ◽  
Enterobacter Cloacae ◽  
Pythium Ultimum ◽  
Plant Diseases ◽  
Disease Suppression ◽  
Acid Uptake

ABSTRACT Interactions between plant-associated microorganisms play important roles in suppressing plant diseases and enhancing plant growth and development. While competition between plant-associated bacteria and plant pathogens has long been thought to be an important means of suppressing plant diseases microbiologically, unequivocal evidence supporting such a mechanism has been lacking. We present evidence here that competition for plant-derived unsaturated long-chain fatty acids between the biological control bacterium Enterobacter cloacae and the seed-rotting oomycete, Pythium ultimum, results in disease suppression. Since fatty acids from seeds and roots are required to elicit germination responses ofP. ultimum, we generated mutants of E. cloacaeto evaluate the role of E. cloacae fatty acid metabolism on the suppression of Pythium sporangium germination and subsequent plant infection. Two mutants of E. cloacaeEcCT-501R3, Ec31 (fadB) and EcL1 (fadL), were reduced in β-oxidation and fatty acid uptake, respectively. Both strains failed to metabolize linoleic acid, to inactivate the germination-stimulating activity of cottonseed exudate and linoleic acid, and to suppress Pythium seed rot in cotton seedling bioassays. Subclones containing fadBA or fadLcomplemented each of these phenotypes in Ec31 and EcL1, respectively. These data provide strong evidence for a competitive exclusion mechanism for the biological control of P. ultimum-incited seed infections by E. cloacae where E. cloacaeprevents the germination of P. ultimum sporangia by the efficient metabolism of fatty acid components of seed exudate and thus prevents seed infections.

scholarly journals Interactions Between Myxobacteria, Plant Pathogenic Fungi, and Biocontrol Agents

Plant Disease ◽  
2002 ◽  
Vol 86 (8) ◽  
pp. 889-896 ◽  
Author(s):  
C. T. Bull ◽  
K. G. Shetty ◽  
K. V. Subbarao
Keyword(s):  
Biological Control ◽  
Phytophthora Capsici ◽  
Trichoderma Viride ◽  
Pathogenic Fungi ◽  
Pythium Ultimum ◽  
Soil Fumigation ◽  
Plant Pathogenic Fungi ◽  
Biological Control Agents ◽  
Lytic Enzymes ◽  
Wide Range

Myxobacteria are soil dwelling gram-negative gliding bacteria that form fruiting bodies containing myxospores. Although myxobacteria produce a wide range of antibiotics and lytic enzymes that assist in their ability to prey on other microorganisms, their role in agriculture has received little attention. Myxococcus spp. were isolated from soils in organic and conventionally managed strawberry production and transplant fields in the absence of soil fumigation. Fumigation with methyl bromide and chloropicrin virtually eliminated these organisms from soil. However, soil fumigation had no effect on the frequency of isolation of Myxococcus spp. from strawberry roots. Six Myxococcus spp. were tested in vitro against eight soilborne plant pathogenic fungi (Cylindrocarpon spp., Fusarium oxysporum f. sp. apii, Phytophthora capsici, Pythium ultimum, Rhizoctonia spp., Sclerotinia minor, Verticillium albo-atrum, and V. dahliae) and against two fungal biological control agents (Gliocladium virens and Trichoderma viride). Phytophthora capsici, Pythium ultimum, Rhizoctonia spp., S. minor, and T. viride were completely inhibited by all of the Myxococcus spp. tested. F. oxysporum f. sp. apii was the least sensitive to the myxobacteria, and no inhibition occurred with some Myxococcus spp. Inhibition of the other fungi tested was variable. Myxococcus coralloides inhibited nearly all the fungi tested. The ability of bacterial biological control agents to produce antibiotics and other secondary metabolites determined whether or not they were lysed by myxobacteria. Secondary metabolite production regulated by gacS protected Pseudomonas fluorescens strain CHA0 from lysis by myxobacteria. More specifically, phenazine antibiotics produced by Pseudomonas aureofaciens strain 30–84 protected it from lysis.

scholarly journals Mixtures of Plant-Growth-Promoting Rhizobacteria Enhance Biological Control of Multiple Plant Diseases and Plant-Growth Promotion in the Presence of Pathogens

Plant Disease ◽  
2018 ◽  
Vol 102 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Ke Liu ◽  
John A. McInroy ◽  
Chia-Hui Hu ◽  
Joseph W. Kloepper
Keyword(s):  
Biological Control ◽  
Plant Growth ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Plant Growth Promoting Rhizobacteria ◽  
Pythium Ultimum ◽  
Plant Diseases ◽  
Disease Suppression ◽  
Plant Growth Promoting ◽  
Growth Promoting

Several studies have shown that mixtures of plant-growth-promoting rhizobacteria (PGPR) could enhance biological control activity for multiple plant diseases through the mechanisms of induced systemic resistance or antagonism. Prior experiments showed that four individual PGPR strains—AP69 (Bacillus altitudinis), AP197 (B. velezensis), AP199 (B. velezensis), and AP298 (B. velezensis)—had broad-spectrum biocontrol activity via antagonism in growth chambers against two foliar bacterial pathogens (Xanthomonas axonopodis pv. vesicatoria and Pseudomonas syringae pv. tomato) and one of two tested soilborne fungal pathogens (Rhizoctonia solani and Pythium ultimum). Based on these findings, the overall hypothesis of this study was that a mixture of two individual PGPR strains would exhibit better overall biocontrol and plant-growth promotion than the individual PGPR strains. Two separate greenhouse experiments were conducted. In each experiment, two individual PGPR strains and their mixtures were tested for biological control of three different diseases and for plant-growth promotion in the presence of the pathogens. The results demonstrated that the two individual PGPR strains and their mixtures exhibited both biological control of multiple plant diseases and plant-growth promotion. Overall, the levels of disease suppression and growth promotion were greater with mixtures than with individual PGPR strains.

scholarly journals Molecular Phylogenetic Analyses of Biological Control Strains of Trichoderma harzianum and Other Biotypes of Trichoderma spp. Associated with Mushroom Green Mold

1999 ◽  
Vol 89 (4) ◽  
pp. 308-313 ◽  
Author(s):  
M. D. Ospina-Giraldo ◽  
D. J. Royse ◽  
X. Chen ◽  
C. P. Romaine
Keyword(s):  
Biological Control ◽  
Plant Pathogens ◽  
Phylogenetic Analyses ◽  
Consensus Sequence ◽  
Nuclear Ribosomal Dna ◽  
Reference Sequence ◽  
Transcriptional Unit ◽  
Trichoderma Spp ◽  
Green Mold ◽  
Wide Range

A polymerase chain reaction-amplified DNA containing the internal transcribed spacer (ITS)-1, 5.8S, and ITS-2 regions of the nuclear ribosomal DNA transcriptional unit was sequenced for 81 isolates of Trichoderma spp. associated with mushroom culture or used for biological control of plant pathogens. Phylogenetic analyses revealed that the biocontrol isolates were more closely related to an isolate of T. harzianum biotype 1 (Th1) than to the aggressive biotypes 2 and 4. Th1 has been isolated from mushroom compost but is not the cause of widespread green mold epidemics that have occurred during the last 12 years in Europe and North America. Three isolates of T. harzianum obtained from shiitake (Lentinula edodes; Shi1B and S3-96) and maitake (Grifola frondosa; Mai1) substrates were placed within the biocontrol group. We also found evidence suggesting that some isolates of T. harzianum originally identified as Th4 from Pennsylvania are more closely related to Th2 from Europe. Finally, considering the wide range in sequence distribution of our samples, we propose that the consensus sequence found in this investigation be used as the reference sequence for further studies involving the identification and taxonomy of T. harzianum.

scholarly journals Identification of an RTX determinant of Burkholderia cenocepacia J2315 by subtractive hybridization

2006 ◽  
Vol 55 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Paul W. Whitby ◽  
Timothy M. VanWagoner ◽  
Ashlee A. Taylor ◽  
Thomas W. Seale ◽  
Daniel J. Morton ◽  
...  
Keyword(s):  
Burkholderia Cepacia ◽  
Plant Pathogens ◽  
Subtractive Hybridization ◽  
Burkholderia Cenocepacia ◽  
Suppressive Subtractive Hybridization ◽  
Phenotypic Traits ◽  
Expression Studies ◽  
Haemagglutinating Activity ◽  
Single Fragment ◽  
Gene Expression Studies

This study utilized suppressive subtractive hybridization between the clinical isolate Burkholderia cenocepacia J2315 and the closely related environmental isolate Burkholderia cepacia ATCC 25416T to isolate DNA fragments specific to B. cenocepacia J2315. Analysis of the resulting pools of B. cenocepacia-specific DNAs identified several fragments that may be part of putative virulence factors. Further in silico analysis of a single fragment indicated that it was internal to a gene of which the predicted product had characteristics of repeat in toxin (RTX)-like proteins and high similarity to proteins in other human or plant pathogens. In conjunction with this finding, phenotypic traits associated with known RTX proteins were assessed. A haemagglutinating activity of B. cenocepacia J2315 was identified that was absent in B. cepacia ATCC 25416T. The expression of this activity appeared to be growth phase-dependent. Analysis of the gene presence and haemagglutinating activity across the species of the B. cepacia complex showed that both were common to the ET12 lineage of B. cenocepacia, but were absent in the other species examined. Haemagglutinating activity was limited to isolates with the RTX-like gene. Expression studies utilizing quantitative PCR demonstrated an association between onset of haemagglutinating activity and increased expression of the gene, which suggests that the putative RTX determinant encodes a haemagglutinating activity.

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